Pre-operative low muscle mass is associated with major complications and lower recurrence-free survival after gastric cancer surgery.

Background Low muscle mass (LMM) has been associated with post-operative morbidity. This study aimed to examine the relationship between pre-operative LMM and major post-operative complications and survival in patients undergoing curative resection for gastric cancer. Methods A single-centre retrospective cohort study was conducted on consecutive patients who underwent surgical resection for gastric adenocarcinoma between 2008 and 2018. Patient demographics, radiological parameters, pathological data and complications were recorded. Skeletal muscle index was calculated using OsiriX software by manually measuring the cross-sectional skeletal muscle area at the third lumbar vertebra and correcting to the patient's height. Univariate and multivariate analyses were used to identify the risk factors associated with the outcomes. Results A total of 62 patients (36 males, mean age 68.3 ± 1.5 years) met the inclusion criteria. Twenty-six (41.9%) patients had LMM pre-operatively. Demographic data in the non-LMM and LMM groups were equally matched except for body mass index (27.6 ± 0.8 kg/m2 versus 24.3 ± 1.1 kg/m2 ; P = 0.012) and serum albumin (36.7 ± 0.7 g/L versus 33.8 ± 1.0 g/L; P = 0.017), which were higher in the non-LMM. LMM was associated with higher incidence of total (35.5% versus 64.5%; P = 0.006), minor (40% versus 60%; P = 0.030), major (9.1% versus 90.9%; P = 0.004) post-operative complications and decreased recurrence-free survival (hazard ratio 2.29; 95% confidence interval 1.10-4.77; P = 0.027). Conclusion LMM is a significant independent risk factor for major post-operative complications and recurrence-free survival after gastrectomy. Pre-operative identification of LMM could be a useful tool for prognostication and may identify a group suitable for prehabilitation.